Cycles of Vengeance
by servantofclio
Summary: Shredder got the vengeance he wanted: the destruction of his enemies. With the turtles mutated beyond recognition, Karai and April must team up to try to bring them back. They'll also have to decide how far they're willing to go. (AU, alternate ending to "Vengeance is Mine." TMNT 2012)
1. Chapter 1

Written for the TMNT Mini Bang 2014. I had this idea rattling around in my head since I saw "Vengeance is Mine;" I just kept wondering, what if things had gone according to Shredder's plan? What if the turtles were mutated, rather than Karai? The mini bang was the perfect opportunity to work out the idea, even though it kept growing and growing. Thanks to theherocomplex for all the encouragement and organization!

* * *

><p>Afterward, Karai sits in her room—not a cell this time. She's been restored to her own bedroom, with a door that she can open by herself, and all her things exactly as she left them. It's eerie, as if she had only stepped out for a moment.<p>

There's one big difference, though, and it sits in front of her: a tank, or terrarium, glass-walled, with sand in the bottom, and the four serpents twining among themselves.

Karai doesn't know much about reptiles, but she suspects it's too cold for them. The living quarters are kept on the cool side, because Shredder believes it promotes health and vigor. The tank is only a glass cage, hastily arranged to house its four occupants. There is water, but no heater. Already, she thinks, the snakes grow sluggish. They do not move around as much, but gather together. Do they remember what they were? Who they were? Do they remember each other, or her?

One of the snakes fixes her with a cold, glassy eye, not brown or blue or green, but greenish-yellow. Karai does not know which one it was. They all look much like, mottled yellow-green scales, wedge-shaped heads, pointed fangs. She can't tell if they recognize her, if any of their former wits and skills remain. She can't tell whether they are afraid, or angry. Stockman had said they were only snakes, no more than animals, cold-blooded, slow, not—

Karai wishes she could be as cold. It would be simpler if she could see them all as her enemies, worthy of any ruthless retribution. She'd been taught to be cold.

Right now, it would be pleasant to be ice. Anything would be better than the mess of emotions churning through her chest. She doesn't know if she can sort out the tangle and name them all right now, but she knows that first among them is anger. No, _rage_. Her father—or, at least, the man who raised her, and who called her daughter not an hour ago, before he sent her to her room with her new _pets_—used her as _bait_. Dangled her over a vat of mutagen that could have turned her into a _thing_, as if she were disposable, all in service of his vendetta. He was prepared to risk her for that, and if his plan hadn't worked, it would be she with the scales and the torpid eyes, coiled in a glass tank. The betrayal in that shakes her to the core and gives her a slight sense of nausea. It would have been so easy for something to go wrong, and their clan's fights against the turtles and their master have been anything but predictable.

She wraps her arms tighter around her knees against the sense of hot shame that that brings up. All her life, she was taught to despise Hamato Yoshi. He was treacherous, she was told again and again, and weak, unworthy. But Splinter had taken her into his home, placed no pressure on her to make a choice and declare her loyalty. He and his sons had come for her when they didn't have to, had risked their own lives for her.

If that was weakness, Karai doesn't think she understands strength.

Leonardo had never truly seen her as an enemy, either, for the entire duration of their acquaintance. She had thought that foolishness more than once, an unforgivable weakness, in spite of his skills. Now, the certainty he had always expressed about her true nature leaves her heartsick and confused. And his brothers—they had never trusted her the same way, and she can't blame them for it. But they had come for her, too, and they had tried to welcome her into their home as best they could, and the result had been... this.

The snakes lie quietly in their tank, now. She should see about a heater, or... something. Even the fact that the tank is here, in her quarters, is a message. It is a lesson, or a test, or a reminder. The Shredder intends her to learn something from this, or he intends to test her loyalties, now that she has nowhere else to go.

Karai tightens her jaw, frowning at the tank. There is no one she can talk to about this. It isn't even safe to speak her thoughts out loud here, in the privacy of her room. There could be listening ears, or listening devices, anywhere. She dares not even breathe an apology to the creatures behind the glass.

But she cannot let this stand. Her father turned on _her_, used her as an instrument for his revenge. Has she ever, her whole life, been anything more than a prop for his schemes? She can't be sure any more.

He thinks he's won. He thinks his vengeance is complete with the turtles' transformation, with Splinter's death. He's so very wrong. But Karai will need to play this carefully. She has been locked away too long; she needs to understand how matters stand within the clan, and she needs to keep her own counsel until she's sure.

There's just one person she can think of who might be able to help her, who might be interested in some revenge of her own. Even getting out of the Foot compound unobserved will be a challenge, but having even a single ally could be worth it.

#

Donnie isn't answering his phone.

Donnie _always_ answers his phone when April calls, usually on the second ring, sometimes even if he's in the middle of a fight.

After the third try, April tried calling Leo, and then the others. Radio silence all around. She almost called the cheese phone, too, but her fingers hesitated on the button. The cheesephone is for emergencies, and she doesn't know if this qualifies as an emergency.

Sometimes the guys were out on a mission, or a training exercise, or something where they couldn't answer their phones, but they'd usually send her a message first. This unplanned, unannounced silence pulls at April's senses. It feels wrong.

Actually, the whole day has felt wrong. She woke up from muddled dreams she couldn't quite remember, but that left her unsettled and drooping. She picked at her breakfast and tried to brush off her dad's concern.

At school, everything feels too loud and too bright. April manages to track down Casey between classes. "Have you heard from the guys at all?" she asks, not caring how it looks that they're having a whispered conversation in the hall, with everyone chattering and bustling around their lockers.

He shakes his head. "Nah, not since yesterday. Why?"

April bites her lip. "I don't know... I just... I keep calling and... I don't have a good feeling about this."

His eyes light up. "We should go check it out."

"After school?" April suggests.

The bell rings. They're both going to be late to class. Casey raises an eyebrow, his usual sly grin spreading over his face. "You wanna wait that long?"

April wavers. Unlike Casey, she tries not to cut class, but... no, she doesn't want to wait.

The lair is empty.

"Hello, anyone home?" she calls as they step through the turnstiles. "Donnie?"

"Yo, Raph!" Casey shouts, right behind her.

But their voices echo against the concrete and pipes, and April looks around, bewildered. Empty. It looks pretty much the same as always—the power's on, there are comic books scattered around the living room, and somebody's skateboard is propped against the ledge. "Hello?" she tries again, but the room seems to swallow her voice. "Check the bedrooms," she tells Casey, and goes to the dojo herself. Everything there appears as orderly as usual. She ventures toward the screen—where she's never been before—and has to force her voice above a whisper. "Master Splinter?"

There's no answer, and when she finally summons her courage and pushes the sliding screen back, there's no one there. The bedding looks rumpled, but everything else is tidy. No blood.

She turns away and leaves the dojo, her heart hammering.

"Nothin' in the bedrooms," Casey reports, coming back with a frown on his face.

"They must have left," April says, half to herself. They left without warning, though, and they'd left behind... everything. All the weapons and equipment are still in place, so they left in a hurry... and she can't imagine why, or where they could have gone without a word to her. She walks into the kitchen and opens a cupboard, at random. No, they didn't take food, either, just about everything seems to be in place. She opens the freezer, and Ice Cream Kitty mews and offers her a fudgesicle.

They went somewhere in a hurry and they haven't come back, and they're not answering their phones. April frowns. Her heartbeat feels loud in her ears.

"What do you think happened?" Casey asks.

"I don't know," April replies slowly.

There's nothing more to do here, so she walks back to the turnstiles, her footsteps dragging as she tries to puzzle it out. Kraang? Foot? Something else? What could have happened?

Out in the tunnel, a strip of black separates itself from the shadows and says, "Thought I might find you looking around here."

April yelps and her tessen is in her hand at once. She braces herself, but Karai faces her with open hands, hip cocked to one side, not attacking.

"Whoa," Casey says. "Is this that ninja chick you were talking about?"

April ignores him. "What did you do with them?" she hisses.

Karai's lip curls, her nose crinkling. "_I _didn't do anything. It was Shredder."

"I don't believe you!" April snarls.

Karai's eyes flick away for a moment. She lips part as if she's going to speak. Then her mouth draws tight and her shoulders hunch. "You're right," she says. "I made a mistake."

"Where are they?" April demands. "What happened?" She's proud that her hand stays steady, and half aware of Casey tensing at her back. He'll back her up. She's got that, at least. She doesn't know if the two of them could take down Karai, but at least they're two and she's one. That's something.

Slowly, Karai extends her arm. April tenses, but there's no weapon.

Clenched in Karai's fist is a bunch of fabric.

No.

Four strips of fabric.

Just as slowly, April puts out her free hand and takes them. Her fingers feel numb as she closes them around the four familiar strips. Red. Blue. Orange. Purple.

She can't stop the tears from springing to her eyes, then.

Casey says, "What the fuck are you— that's messed up."

April clenches her fist around the four masks. "Are you telling me they're dead?" she says, unable to stop her voice from shaking.

Karai's mouth twists. "My f- Splinter is. I saw Shredder kill him myself. The turtles, no, but they're—"

"Where are they?" April demands, her body quivering with rage. She doesn't know why Karai's here, but she _will_ storm Foot Headquarters by herself if she has to—

"—mutated," Karai finishes.

"Dude. They were already mutants," Casey says.

Karai sneers at him. "They mutated _again_, all right? They're snakes now." Her eyes flick away for a fraction of a second. "I don't—Stockman says they're not intelligent. It wasn't regular mutagen, it was something he cooked up. I don't know. I have them in a tank in my room."

Mutated. All the breath seems to go out of April's lungs, because this... this they can _deal_ with, right? There has to be a way. They found a way before, or... Donnie did.

Behind her, Casey bursts out in a sharp bark of laughter. "You have them in a tank in your room? What the hell? That's _weird_."

"Oh, and what do _you_ think I should do with them?" Karai snaps back.

April says, "If they're... if they mutated, then maybe... the retro-mutagen..."

Karai's eyes cut quickly from Casey to April, widening. "Retro... you mean there's a way to undo it?"

"Maybe it would be different for mutating mutants," April says doubtfully. "But Donnie invented a retro-mutagen." Her grip on the masks tightens.

"Where is it?" Karai demands, leaning forward. April holds up her fan defensively, taking a step back, and Casey steps forward, putting them almost shoulder to shoulder.

"There isn't any more just lying around," April says. "It was hard to make—it needed a lot of mutagen, and..."

"But you can make more, right?" Karai says.

April's heart clenches with dread. She knows her DNA is part of it, but... Donnie's the only one who knows how to make the retro-mutagen.

_Donnie_. He worked so hard to make the retro-mutagen and help April's dad, to do the impossible, and now he's the one who needs help. She looks down at the masks dangling limply from her hand, red and orange and blue and purple. "I'll figure it out," she says. Her voice only wavers a little. "I'll go over his notes. He must have written it down. But, um... I'll need some mutagen to test it with. It would help to have a sample of... the kind that got used on them."

Karai nods, her eyes bright. "I can do that. Give me a little time, and I'll get some from Stockman's lab."

"Wait a minute," says Casey, coming up to stand next to April. "Why do you care? Aren't you, like, the enemy?"

April opens her mouth to say it's more complicated than that, and closes it, deciding that's not her place. Karai scowls at him. "You don't know anything about me, punk." After a moment, she adds, more quietly, "But I owe them."


	2. Chapter 2

Dad says, "April, no."

April stares at him in utter shock. Something sour seems to slide down her throat and curdle in her stomach. "But—"

"I'm sorry about the turtles, honey, I am," her dad says. "I really am."

"If you were really sorry, you wouldn't say no—" she says, voice rising, but Dad's voice rises too, carrying over hers:

"But it's just too dangerous, sweetheart, the aliens are bad enough, but this Shredder—"

"—I can't just leave them, Dad, they're my friends—"

"_April Marie_," her dad says, in a voice that stops April's in her mouth. "For once you will _listen_ to me and _do as I say_."

The sour feeling in April's stomach only grows as she stares back, mute, her hands shaking. Her father pauses, as if to make sure that she's going to stay quiet, before continuing. "This man is _dangerous_, honey. He's a- a _crime lord_. They're involved in all kinds of things you don't need to know about. And this business with new mutagen—no, April. No. I'm sorry, but I'm putting my foot down. Stay away from this."

"I'm immune to mutagen," April says, the words tumbling hot and bitter out of her mouth.

"You're not immune to _guns_, April! Or swords!" He stops, breathing heavily, and his eyes shift from side to side. He swallows, his hand drifting up to touch the side of his neck. "I'm sorry about your friends," he says.

"They saved me. Over and over," April says. "They— Donnie saved _you_, Dad, twice, and they never gave up, not ever—"

"I said no, April."

He's looking back at her now, not watching the fly zipping around the room or staring out the window, and his expression has hardened. April stares back. She can count on the fingers of one hand the number of times he hasn't let her have her way, all the way back to the day of her mother's funeral. And every time he _didn't_ let her have her way, he looked at her like this, trying to be stern, trying to make his eyes like ice.

Once upon a time, she might have pouted or whined or kept wheedling, cried or begged, thrown herself to the ground and refused to budge. All that was before, though. Before she had to get along without her dad. Before she had to stand up to the Kraang and their probes in her brain. Before she became a _kunoichi_.

April runs her thumb over the calluses her _tessen_ left on her palm. She remembers Splinter telling her that a _kunoichi_'s best weapon is deception.

Her father has no idea what she's capable of.

She blinks her eyes and lowers her chin. "Okay, Dad," she says, soft and sad. "I understand."

Her father lets out a relieved breath and pats her shoulder. "I really am sorry," he says.

She looks up at him through her bangs. He's giving her an anxious, wavering smile.

She gets it. He just wants her to stay safe. He doesn't understand that there are things more important to her than safety.

"Damn, Red," Casey says, later, when April tells him what her father said. "What're you gonna do?"

She frowns at him. "What do you think I'm going to do? I'm going to figure out this retro-mutagen. I just need to hide it from my dad, that's all."

Casey nods, unusually serious. "You go, Red. I got your back." He breaks out in his usual smirk. "You know you'll get the goal with Casey Jones running interference."

April laughs and punches him in the shoulder, and for a moment things are almost normal again.

#

Everyone looks at her differently now. The lower-ranking Foot ninja shy away from Karai, not meeting her eyes, but sneaking looks at her behind her back. Shredder's lieutenants are different; their inhuman eyes follow her all the time. Tiger Claw stares at her from his towering height, as if she's an interesting piece of prey. Bradford, or what's left of him, slinks into the dojo to watch her train, as if he is sizing her up. She catches Xever's round fish eyes watching her wherever she goes.

Karai holds her head high and her shoulders back. She strides around the compound as if nothing has changed, as if she had never been locked in a cell for having the temerity to question her paternity. She trains, she goes on missions as she is ordered, commanding the ninja and their robots. She is never paired with one of the other lieutenants. No one seems to have observed her unauthorized departure, when she found April O'Neil and her friend. Karai does not allow herself to relax, not quite, but her confidence grows by degrees.

One day, Xever breaks the silence. "It could have been you, you know."

They are passing in the corridor, Karai on her way to dinner. She pauses in place. "Excuse me?"

"In the vat," Xever says, rubbery lips curling back to show his sharp teeth. "You could have ended up like us."

Xever used to flirt with Karai, back when he was a man. Back in Tokyo, before she had ever been to New York. It seems like a long time ago now, but she still remembers. She had flirted back, a little, quietly, discreetly, not under her father's stern eye. Xever had never tried anything beyond smiles and compliments and offering her a cigarette when she was fifteen. She had liked him; they had been friends, as much as anyone had friends in the Foot clan. He was not a ninja, but he respected their ways, did her father's bidding, and Karai knew very well that Xever was useful to her father because he would do things even the ninja would not do.

He respected her, too, offered to show her a trick or two from street fighting, and acknowledged her skills. Not like Bradford, who treated her like a little girl playing dress-up, even though he had started ninjutsu much later in life than she had, had had to unlearn old martial arts to learn their ways. He always underestimated her, but she would not make the same mistake. She had stolen into the dojo to watch him, hiding herself in the rafters, silent as a shadow. Sometimes Xever had even come with her.

It had been strange to come to New York and find the pair of them so changed. It is difficult, even now, to see the lean face and dark eyes and blade-like smile she once knew in the face of the fish.

But this is her opportunity, so she lets her mouth turn down, lets her eyes soften, and says, "I know. I know it could have been me. I didn't really understand before, Xever—"

He snorts, wide mouth opening to let out the puff of air. "You didn't care to understand."

"I didn't," she agrees, ducking her head a little. She doesn't apologize; she's not good at apologies. Xever would suspect one in a moment. "I wish— do you think there's any way for you to be human again?"

Xever huffs again. "Stockman says he's working on it."

"Oh," she says, and lets the word lie there. She knows how little respect any of them have for Stockman.

Sure enough, Xever's round eyes roll. "Probably just keep it for himself," he mutters.

"If he doesn't screw it up," Karai says.

Xever's eyes roll again, and he laughs, a strange sound coming out of that month. "That is hardly likely, no?"

She gives him a quick smile— "Not very, no"— and lets her expression grow pensive again. "Now I suppose the turtle could have done it—"

"And how _are_ your new pets?"

Karai shrugs one shoulder. "—or if my father really wanted to find a cure, maybe he'd find a real chemist or geneticist, but—" She starts to turn away.

"And doesn't he?" Xever demands, planting his robotic feet.

Karai looks back over her shoulder, deliberately widening her eyes. "What do _you_ think?"

A flicker passes over his face that she can't read. But it's obvious, isn't it? The mutants are dependent on the Foot clan, and stronger than they were. Why should he want them to be restored to their old selves?

After she lets that sink in, Karai glances swiftly side to side and draws close enough to Xever to whisper, "But I promise you, someday, when I take over the Foot clan—"

"You presume much," Xever hisses back.

Karai draws herself up. "I am in my father's favor again, am I not?"

"True," he allows. "But your father is still vigorous, girl. You will not lead this clan for a long time."

"True," she returns. "But I keep my promises."

She turns again, and this time he lets her go. She does not let herself smile. She has planted a seed, that's all. Let Xever think it over. Let him consider his loyalties and where his best advantage lies.

Let _him_ be the one to come to _her_ and say, as if it were entirely his own idea, "What if we removed Shredder?"

#

Donnie's notes are _impossible_.

Oh, he took meticulous notes on everything, but the paper journal just has records of things done, quantities of components and the like, and it's heavily abbreviated. On top of that, the marginal notes are half in English and half in Japanese, which April only speaks a few words of. That means she's going to have let Karai read them to see if there's anything important in those notes, and she hates the idea of letting Karai get her hands on these notebooks. They're just so... so _Donnie_. The earliest ones must have been cribbed out of the trash, because there are weird stains on the cover and some of the pages in the front are missing, and someone else's handwriting is crossed out, the notebook relabeled and dated in Donnie's blocky print. The later ones are ones she bought for him, so they're neat and square and almost unblemished, except for occasional spots that look like dried ice cream or pizza grease, even though every notebook is labeled "MIKEY DO NOT TOUCH" on the front. There are random doodles on the pages, too, including little stick-figure illustrations of her—she can tell because of the ponytail and the fan in her hand. If she can't figure this out, these notebooks and the tessen might be the only things she has to remember him by, or any of them—the best friends she ever had, and she didn't even say goodbye properly the last time she talked to Donnie—

When she thinks about things like that, April finds a lump in her throat, and her eyes get too blurry to see what she's trying to read. So she tries really hard not to think about it, and mostly succeeds, except for when she throws herself in bed at night and tosses and turns, too wired from the day's dose of caffeine to fall asleep easily.

What's worse than the paper notes are the files on Donnie's computer, where he was doing all the theoretical work. That's where the real stuff is. April could probably duplicate Donnie's retro-mutagen from the lab journals, but to tweak it? To change the formula so it'll work on the altered mutagen Stockman dosed the turtles with? For that, she's going to need the theory, and those files are encrypted.

So now April has to be a codebreaker as well as a geneticist, and she's been trying, but every time she thinks she's getting somewhere, she gets a string of gibberish and has to go back to square one. She's been at it for weeks now, and meanwhile the guys are sitting in a terrarium in Karai's room.

April remembers how long it took Donnie to invent the retro-mutagen in the first place, and it makes something cold trickle down her spine. She wishes so much that she'd listened better, or tried harder to stay awake in the lab and help. Something, anything, so that she'd have more of a clue what she was doing now. Karai's willing to help, but she knows a lot about ninjutsu and not much about science, so her help is limited to stealing the mutagen samples April needs. Casey can't help much either, though he brings her food and energy drinks and runs interference with her dad.

April mostly can't work at home; she keeps her notes and the files she copied from Donnie's laptop in her locker at school, and takes to working in the library whenever she can. Sometimes she goes down to the lair, but it's much, much too quiet and cold and lonely down there. She comes to have a usual corner that she stakes out, setting up her computer and the papers around her like a fortress. Usually no one disturbs her.

This day she's too busy trying yet another method of decryption, and while the program runs, she flips through one of the notebooks, looking for anything useful, and freezes when she sees "D + A" written into a margin. April's eyes start to sting. She shoves the whole stack of notebooks away from her, hard enough that some of them fall to the floor. Her computer beeps at her softly: another failed attempt. April grinds her teeth and rubs her eyes. She doesn't know what to do next. She's stuck, spinning her wheels uselessly, and Casey's only interested in science that blows up, so he can't help, and her father _won't_ help, and the turtles are _snakes_, and—

It's all too much. When her father was taken before, at least she had the turtles to keep her company, and when her father was mutated, she had her anger to hold onto. Plus, she knew the turtles were out there, all the same, keeping up the fight and the search when she couldn't. It comforted her even when she was angry with them.

April's vision blurs. She pushes herself away from the table and reaches, blindly, for the fallen notebooks. A familiar voice says, "April, are you all right?"

"I'm fine." April hunches her shoulders. Irma's presence just reminds her of how she's screwed that up, too. Irma still tries to be her friend. It's not her fault that April has secrets to keep.

"Let me just help you pick these up," Irma says, crouching down on the opposite side of the heap of papers from April.

April wipes her eyes again. "No, that's fine, I've got it," she says, but she reaches for the stack of notes too late. Irma's already gathering the papers into her hands. April hesitates; she can't very well just yank them away.

There's a pause where she hears the rustle of the papers in Irma's hands. She holds out her own hand, hoping that Irma will just turn them over, no problem.

But Irma says, "April, what are you doing researching mutagen?"

"Nothing!" says April, too high-pitched. She scoops up a couple of notebooks, and a horrid thought crosses her mind. "What do you know about the mutagen?"

"What do I know about _what_ mutagen?" Irma says. When April looks up, finally meeting her eyes, she's frowning, and pushes up her glasses with one hand. "Mutagen just means a substance that tends to cause alterations to an organism's DNA. But that kind of thing is dangerous, April, why would you be messing around with it?"

"I know," April snaps. "Believe me, I know it's dangerous. But I have to do it, and you wouldn't believe me if I told you, so why don't you forget we even had this conversation?" She reaches for the journals.

Irma lets her take them, but she doesn't go away. Instead she hesitates while April gathers up all the notebooks—she's going to have to sort them out again and put them in order, yet another thing to do—and then says, "Is this about your dad's disappearance?"

"No." April shoves the notebooks into a stack.

"Because, April, I'm- I'm sorry about what I said, back then—"

"It's fine." Bad enough the police hadn't believed her, but Irma was supposed to be her friend. They were supposed to trust and believe in each other. She hadn't even talked to Irma for nearly a month after it all happened, and they hadn't really made up until April had her father back. The first time, anyway. "It doesn't matter," April says, straightening up to put the stack of notebooks onto her table. The encrypted gibberish still stares at her from her laptop screen.

Irma straightens up with her, looking earnest and worried. She tucks a lock of dark hair behind her ear. "Then— is this about your secret friends again? Because I've hardly seen you in the last few weeks, and you look—"

"It's not what you think," April says, tightening her mouth into a firm line and turning away.

"I'm just worried about you, April, all that stuff with your dad, and now these friends— are you in some kind of trouble? Because if they're dangerous—"

"Don't even," April says. She keeps her voice low, remembering she's in the school library, but there's anger pulsing under her skin. "It's not me who's in trouble, it's my friends, and I'm the only one who can help them, so I'm not going to give up." She turns her back, pointedly, hunching over the laptop again.

There's a moment of silence before Irma says, "And that's why you're researching some kind of mutagen?"

"Just let it go, okay?" Since Irma won't stop hovering behind her shoulder, April starts shoving the notebooks and her notes into her bag.

"Maybe I can help, though. Is that some kind of cipher? Have you done a character frequency analysis?"

"_Yes_, what do you think I've been doing?" April snaps, whipping around to glare at the other girl. "It's not helping. I tried that, and I just keep getting mixed-up characters—"

Irma holds her ground. "Have you considered that maybe there's a transposition cipher _and_ a substitution cipher?"

April stares.

"Of course, it would help a lot if you knew what the transposition key might be," Irma says, adjusting her glasses. "The key is used to divide the text into columns, and then it's scrambled based on the order of letters in the key. Do you know who ciphered it? What might they pick for a key? It's probably not too long a word, should be something easy to remember. Five or six letters, maybe?"

It doesn't take April more than a moment to think of a five-letter word Donnie might have chosen. Her cheeks grow warm. "I might have an idea," she whispers. "How do we use the key?"

It's not difficult to write a script that will use the key APRIL to rearrange the text, and then, when April tries the character frequency analysis again, words start to appear. Real, beautiful words. They start swimming before April's eyes, and she buries her face in her hands.

"April? Are you okay?"

April swallows down a sob and wipes her eyes. Irma is peering down at her anxiously. "Why?" she whispers. "Why would you—"

Irma bites her lip. "You're my friend, April," she says. "And you've been looking just _miserable_, lately, and I know I haven't always been the best friend, but I want to help you if I can."

April takes one slow breath after another, nice and even, like Sensei taught her, trying to get her tears under control. "We have to get to class," she says, "but can you meet up after school?"

Irma nods, wide-eyed.

April breathes out, feeling the tightness across her chest loosen just a little. "At the noodle shop. Murakami's. I'll— I'll explain. I'll explain everything."

* * *

><p><em>Author's Note: For the purposes of this story, Irma is a real girl.<em>


	3. Chapter 3

"You've got to realize, this sounds—"

Casey interrupts. "Look, Irma, if you don't believe it, just walk away now."

Irma drops her chopsticks and glares at him. "That's _not_ what I was going to say, Casey Jones. I mean, it _does_ sound incredible, but there have been a lot of weird things happening in the last year. Honestly, the alien stuff is easier to believe than the whole ninja clan feud thing. And I still don't completely understand about the mutations, either."

Casey groans, turning to April. "Why do you think we need her again?"

"Oh, I don't know, maybe because I know for a fact that Irma gets A's in math and chemistry _and_ bio?" April snaps. Casey scowls, his lower lip jutting out, and Irma sits back in her seat, looking smug.

"Yeah, but can we trust her?" Casey asks.

Now it's Irma's turn to scowl. "I'm right here! Stop talking about me like I'm not!"

"Maybe I just _wish_ you weren't."

"Guys!" April smacks her folded fan down on the table with a clang. "Cut it out!"

Casey protests, "I wasn't even doing anything!"

April glares at him until his shoulders hunch. "Stop being a jerk to Irma," she snaps. "Stop baiting her, stop acting like she's an intruder, just stop, okay?"

"Yeah, _Casey_."

"Irma, you're not helping!" April heaves a sigh and closes her eyes, pinching the bridge of her nose. A brief, stabbing sense of sympathy for Leo overwhelms her, followed by a surge of longing that he were actually _here_, and April didn't have to be in charge of these two. She sighs again and opens her eyes. Irma and Casey are both looking sullen and cross. "Look," she says. "You don't have to like each other. But if you're both serious about this, we all have to work together. We've got the notes deciphered now, but I still need help to figure out how to alter the formula, so yes, Casey, I need Irma's help. And I need Casey's help, too, Irma, because there's probably going to be some fighting before all this is done with. Okay?"

Irma gulps, biting her lip, while Casey mutters, "Hell yeah." When April looks at him, he straightens up a little and says, "Okay, Red, you know I'm in."

"Me too," says Irma quietly. "There's just kind of a lot to take in."

"I know," says April, relieved. "But if we work together, things should be okay. I mean, we're all on the same side, and we're trusting Karai, so we have to be able to trust each other, right?"

Casey nods, and after a moment Irma does, too. April lets out the breath she was holding. She feels better with both of them on her side.

#

The first thing Karai hears when she opens the door to her room is the snakes, hissing.

The first thing she sees is Oroku Saki, without his helmet or gauntlets, standing by their tank. In his shadow, the snakes twist and writhe, more active—more agitated—than Karai has seen them since they were put there. They twine together, coiling under and over each other in such a mass that she can hardly tell which snake is which. The man watches them, and she cannot read his expression.

She closes the door behind her, and does not let her voice tremble when she speaks. "Father?"

"Karai," he says. To any other ear, he sounds his normal self: forceful, authoritative. Master Shredder's word is not questioned among the Foot.

Karai, however, is his daughter, or was raised as such. She hears the moment of hesitation. "Yes, father?"

"How do the creatures fare?"

She lifts a shoulder into a shrug. "They drink and eat and sleep. I am not sure the temperature is right for them. They do not react much."

"They react to me," he says, as if to himself, and adds, "You care for them, then."

"I thought you put them here for me to care for them," she says, cautiously. It is possible she has failed whatever test was set for her.

He is silent for a long moment, staring into the tank. "Once, I called him brother."

Karai waits, and them prompts, "Father?"

"Hamato Yoshi, I mean." He says it with his usual sneer. "When we were young, we called each other brother. It was all a lie."

"I see," Karai says. She finds that she's bracing herself for something, unsure how to respond to this particular mood.

"It was folly," he says. "As much as teaching ninjutsu to these freaks." He raps the glass of the tank with his knuckles, a hollow sound that sets the snakes hissing and skittering once more. "He called _them_ his sons. Mere beasts. Turtles. Ridiculous. He did not understand what it is to be a father." He looks at her, his scarred lip curling away from his teeth.

Karai can hardly breathe. She must force her chest to expand and contract. She must keep from her face that she is thinking about the four of them, all those nights she watched, and that one brief day she spent in their home: the joking, the squabbling, the exasperation, but most of all, how all the bickering fell away when they needed to act together. How Raphael had come for her even though he didn't like her, just because Leonardo had asked him to.

Fortunately, her father does not seem to require a response. "It is a mercy I ended his empty life for him," he says.

Karai blinks. "Yes, father."

He starts toward the door and she moves aside, almost stumbling in her haste. He says nothing more, and she bows her head as he passes, keeps her eyes on the floor until the door shuts behind him. Then she goes to the tank and peers in.

The snakes lie quiet now. One of them lifts its head, forked tongue flickering out. She looks into the cold yellow-green eyes, and lets herself breathe. Shredder's moods have been fey lately, and changeable. Perhaps the revenge he yearned for has not satisfied him, after all.

The phone hidden in Karai's pocket vibrates. She grits her teeth, counting the seconds, and swings into action when the signal continues long enough. She locks her door, douses the lights, mounds the spare blankets strategically in her bed, and then climbs silently into the ventilation shaft.

There is some risk every time she leaves the building alone, which is why they are only supposed to meet when its urgent. She spots the two figures on the rooftop before she gets there, and plans her approach so that she is nearly on top of them before she shows herself. "This had better be good, O'Neil," she says as she drops off the water tower.

They both jump, much to Karai's satisfaction. She ignores Jones, because it annoys him, and focuses her attention on the other girl.

April collects herself quickly. "I think we've got it," she says. "The formula, I mean."

"You and your little geek friend got it done?"

April's mouth purses. Karai is still not entirely pleased that April chose to involve someone else. It feels like family business, not for other eyes and ears. "Irma helped a lot," April says tightly. "And it seems to work on the samples you gave us."

Karai nods. It had been annoying enough to collect those bits of shed skin from the snakes' tank. They had a tendency to try to bite her. "You're sure?"

April's shoulders tense. "I'm... we're about as sure as we can be. We need to test it. I think we have just enough mutagen to make a dose for one."

Karai thinks about the logistics of sneaking one of the reptiles out of the building with her, and makes a face. "Okay. When do you want to do this?"

#

They're waiting for Karai in the lair this time.

April doesn't entirely like meeting her there, and neither does Casey, but... well. Karai already knows where it is, but it should be safe enough from the rest of the Foot. Besides, familiar surroundings might be helpful.

Still, April worries at her lower lip with her teeth as the minutes tick by. Casey lounges on the couch, fiddling with his baseball bat, and Irma sits with her arms wrapped around her knees and her eyes darting around the room. She says, "So... this girl Karai..."

"She's dangerous," April reminds her. "We're allies for now, but we can't count on that lasting."

Irma nods. April wishes she hadn't insisted on being here for this, saying it was her project as much as April's, and she wanted to see how it worked. She's tried to keep some separation between Irma and Karai so far, even though it wouldn't be hard for anyone to track down Irma if they wanted to. April didn't entirely want to bring Irma down here in the first place—it seemed wrong, without the turtles knowing. But the only place they really had to work in was Donnie's lab; they couldn't very well use their school's equipment. She's compromised, leading Irma down to the sewers blindfolded, so she still doesn't know the real location.

"It's okay," Casey says with a smirk. "I'm here to protect you, Irma."

Irma rolls her eyes at him and wrinkles her nose, drawing breath for a retort, but that's when Karai vaults over the turnstiles.

"You're late," Casey calls.

Karai scowls at him. "_You_ try nabbing one of these jerks. They're twisty, and they bite."

"Good for them," Casey says, snickering.

April tries to hide her own giggle as Karai sets down a squirming sack. "You did get one, though."

"Obviously." Karai rolls her eyes. "This must be your lab partner friend, huh?"

"This is Irma," April says as Irma edges a little closer to April, looking from the sack to Karai in fascination. "And this is—"

"Karai." She cuts April off. "Let's hope this works."

"Do you know which one it is?" April approaches the bag cautiously, holding the vial of precious retro-mutagen. The sack has gone still, maybe because of the chilly air in the lair.

"I can't tell." Karai reaches down and unties the sack. "They all look too much alike. You'd think they'd keep their own eyes or something, but no."

April remembers her father's eyes watching her out of the bat-mutant's face, and shivers. "Maybe it's better this way," she says, looking down.

Karai grabs the snake as it slithers out of the sack, keeping it from darting away. April can see what she means. Its eyes are more yellow than anything else, glassy orbs that look at them with no particular intelligence. Its scales are mottled, green and yellow and brown. It's writhing enough that it's hard to tell just how long it is—at least four feet, she thinks, but she can't be sure. Irma peers around April's shoulder and pushes her glasses up her nose. "I don't recognize the species," she says.

"Does it matter?" Karai asks. The snake twitches at the sound of her voice, and she grimaces. "What are you waiting for, O'Neil? Un-mutate it, already."

"I thought ninjas were supposed to be patient," says Casey.

Karai bares her teeth at him. "Don't start with me, Jones."

"Fine," April says. Karai's right, this is what they're here for, after all. She takes the stopper out of the vial, trying to still the trembling of her hands. "Come on," she mutters under her breath as she tips the vial over. "Come on, come on..."

When the retro-mutagen first hits the snake's head, nothing happens. Then it hisses, thrashing wildly until Karai loses her grip on it. They all tense, but the snake doesn't attempt to flee. It continues thrashing, twitching side to side in sinuous curves. April reaches into her pocket and folds her fingers around the four masks she's been carrying there these last bitter weeks. "Come on," she keeps whispering, and thinks _Please, let me get this right_.

Even as she thinks it, the snake's body deforms. It's growing thicker in the middle, four buds branching out from its body. Its hisses drop in pitch and turn into a groan as the buds thicken into limbs and its back rounds into a dome. The shell seems to burst out, cracking into its pattern of scutes, while the snake's tail seems to shrink and disappear and its head re-forms into something rounder. April's heart beats faster, and she's clutching the masks so hard her knuckles hurt.

The turtle stays on all fours, panting, for a few long breaths. Then he lifts his head, gaze passing over them almost blankly, until his eyes land on Karai.

Then he lunges off the floor, hands going for her throat.

Irma shrieks and jumps back, which is just as well, because April's flinging herself forward, trying to grab his arm and pry his fingers away from Karai's neck, calling, "Wait! Don't! Calm down!"

Casey's doing the same, on the other side, and he's the one who manages to get through, shouting, "Raph, dude, chill, she's helping us!"

"_Helping_ us—" Raphael allows himself to be pulled away from Karai only to whirl on Casey. "You can't _trust_ her, Casey, it was all a trap, she—"

"I didn't _know_ that." Karai backs away with one hand to her throat. She has a knife with her other hand.

"I saw what happened to Sensei," Raph spits in her direction. Karai's face twitches and hardens, while her shoulders hunch. Her regret washes through April's head like bitter, black coffee gone cold. Karai says nothing, though, just pulls away another step.

Trying to project calm, April says, "She helped us get you back, Raph."

"Back...?" Raph looks around, yanking his arm out of Casey's grip. "_Where are my brothers?_"

"We didn't—" April begins.

"They're safe back in my room," Karai says.

"The middle of Foot Central is not _safe_," Raph snarls. "So, what, they're still—" He swallows, and an expression crosses his face that April doesn't recognize. Raph's emotions are always easy to read; he's like a roiling cloud of anger standing next to her, a thunderstorm in mutant turtle form, but underneath that—

"Yes," April says, stopping herself from prying. "They're still... mutated. I'm sorry, Raph, but—"

His eyes widen. "You can't just _leave_ them that way, April! What were you _thinking_?"

"We only had enough for one of you!" she says, stiffening. It was the right plan, it was; they don't have enough mutagen for all four, and they needed to test it on one. Donnie would have understood, if he were the one here.

"And you picked _me_?" Raph says. His eyes are so easy to read that April feels a stab of guilt at her own momentary wish.

"I would have grabbed one of the useful ones if I had known," Karai puts in.

Raph's expression hardens, and he turns on her with a growl. Casey shoves himself between the two of them, scowling at Karai.

April scowls at her, too. The least she could do is not be actively unhelpful. "But you're here now," she says, trying to defuse things, "and you can help us with the others."

Raph gives her what is supposed to be a scornful look, but without his mask his eyes are too wide and vulnerable for the right effect. "How? I mean, sure, but—" Glancing around, he seems to notice Irma for the first time. "Uh, who's this?"

Irma waggles her fingers and offers a nervous smile as April does the introductions: "This is my friend, Irma Langinstein. Irma, this is Raphael. Irma helped me make the retro-mutagen."

"And you brought her down here?" Raph asks.

"I don't actually know the way," Irma says. "April kept me blindfolded."

Raph considers that, eyes narrowing. "I guess that's okay, then. But what about her?" He jerks a thumb at Karai.

"She came to us," April says. "We need her."

"No, we don't, cause we can't trust her," Raph says.

"I didn't know it was a trap," Karai snaps.

Raph whirls on her again. "Then you're stupid, and you shouldn't have run off on your own, but you did and now Sensei's d-" He cuts himself off, grief crashing through his face and mind. "— gone," he says instead.

"He _used_ me," Karai snarls, leaning forward. "Shredder used me as bait, because he knew you'd—he knew your father would come for me, and all of you." Her face crumples for a moment and then hardens. "He makes me call him _father_, he's called me daughter my whole life, and he just used me to get at your family."

"So, what, I'm supposed to feel sorry for you now?" Raph is leaning forward, too; Casey still has a hand on his arm, but he could probably break away easily, and April edges closer, not sure what she can do if the two of them really go at it. "Because excuse me, but my brothers are _snakes_ and I saw what your father did to mine."

"I have no father any more," Karai cries, in a voice that makes them all flinch

"Neither do I," Raph snaps back.

They stare at each other for a moment before Karai's eyes narrow and she shakes her head. "Wait. You'd already transformed by then."

"I—" Raph draws back in momentary confusion. "I don't know. I saw it, and then— it seems like the last thing I really remember. Everything after that is weird. Like I couldn't think right, or something."

"Well, I was the one feeding you the whole time. You're welcome." Karai folds her arms. "Leonardo would have believed me," she mutters.

"Don't you dare say his name to me," Raph says. Not shouting, but in a quiet, deadly voice that makes them all twitch.

Karai meets his eyes and nods, a tiny movement, and then unfolds her arms with a jerk. "Look. Believe whatever you want about me, but believe this: I'll help you get them back. I want all of this to be over."

They hold each other's gaze for a long moment, and then Raph turns away. "Fine," he says. "Let's go get them right now."

It takes several minutes to convince him that they need more mutagen, a lot of it, to make enough retro-mutagen, and that they'll have to wait until Karai can steal the access codes to Stockman's lab before getting what they need. It takes even longer to persuade Raph that they can't just go take the snakes right now; if anyone notices they're gone from Karai's room, that's going to raise questions they can't answer, and they'll lose the advantage of surprise.

"So swap 'em with ordinary snakes," he says.

"We don't even know what kind of snake they are!" April says.

"A lot of breeds of tropical snakes aren't legal to sell in the U.S.," Irma puts in. April expects her to flinch when Raph glares at her in response, but she just looks at him seriously and adds, "I'm sorry."

"Fine," Raph says finally. "You go do whatever. I'll just, um—" He looks around, at the old television, the crate full of battered videotapes, the comic books. The silence of the rest of the lair, beyond.

April and Casey exchange glances. There's no way Raph should stay down here by himself, alone in a space that should have been full of family. She could take him home, April thinks, and try to explain to her father, but Casey clears his throat first and says, "Hey, um, my dad's out of town for a week, and my sister's staying with my mom in Connecticut. Why don't you come crash at my place? It'll be cool."

She can see Raph's shoulders slacken as he says, "Yeah. Okay."

With that settled, there's one more thing to do. "Here." April pulls her hand out of her pocket and holds it out.

Part of her is reluctant to let go of the masks, the talismans she's been holding onto ever since it happened. But when Raph looks down at the four folded bands of colored fabric in her hand, the tightness around his eyes and mouth eases, and that makes it worth it.

She was only ever holding them in trust, really. Giving them back to him is the right thing to do.

"Thanks," he says. "Let me get the rest of my stuff."

He goes to the dojo for a spare set of weapons and to his room. When he comes out, he looks like himself again: armed and masked and belted, and April thinks all of them, even Karai, stand a little straighter.


	4. Chapter 4

Getting the access code for Stockman's lab is easy enough. Bradford doesn't have a good memory for this sort of thing, so all Karai has to do is wait until he's training with the lower-ranking ninja before she breaks into his room and finds the piece of paper where he wrote it down.

No, the problem is going to be hauling out the large quantities of mutagen April says they'll need. Stockman can hardly help but notice the absence afterward; they're just going to have to cover their tracks as best they can and work quickly. It was even hard to choose a time when Stockman won't be in the lab, since he sleeps and eats there, too. However, he leaves every few days to scavenge supplies and visit his old workshop. Karai discovered this when she was assigned to follow him, right after she was reinstated. It was a boring evening, tracking the flying mutant while he muttered to himself in buzzing tones that no one else could make out, but it makes her hope that he'll be gone for a few hours.

Tonight's the night. Once she's sure Stockman's gone, Karai sends a surreptitious text to the others and slips down to the lab as soon as she can get away unnoticed. Keeping her hands gloved, she taps in the access code to the lock and ghosts into the lab, sticking to the shadows as she works her way around the room. It's a mess, cluttered with the detritus of Stockman's experiments. He's never been tidy, as far as Karai can tell, and it's gotten worse since he was mutated, especially since he's none too picky about what he eats. Karai holds her breath as she passes one of the smelly piles Stockman favors these days.

Fortunately, she doesn't have to search for anything small; the mutagen is easy to find, stored in large sealed drums against the far wall. Karai locates them first, to make sure Stockman hasn't moved or used up the supply, and then goes out to make sure the way to the loading dock is secure. As far as she knows, the clan isn't expecting any deliveries tonight, and sure enough, the storage area is quiet and unoccupied and the outer door is locked.

And Raphael is waiting outside when she opens the door.

Karai looks around wildly. "You were supposed to come with the van," she hisses.

"Casey and April are bringing it up," he says. "I've been here for an hour already. Just in case."

"Just in case of what? No one's supposed to see you, you idiot."

"No one's going to see me." He follows her inside. "Ninja, remember?"

Karai wrinkles her nose in annoyance. "We're ninja, too. We're not like your little human friends. We know what to look for."

"Yeah, well, no one even knows I'm back, right?" A heavy hand falls on her shoulder. Karai looks back, scowling, to find him staring her down. "Because you didn't sell us out, did you?"

She shrugs off his arm. "Oh, I get it, you still don't trust me."

"Give me one good reason I should."

"How about, I'm all you've got?" Karai snaps.

His eyes narrow and he bares his teeth at her. She turns her back deliberately, continuing to lead the way back to Stockman's lab. If he wants to attack her from behind, he can, but she doesn't think he'll do it. There's too much on the line for him.

And, in fact, he falls in behind her with no more comment. They make their silent way back to the lab, and that's where he speaks next. "So... are my brothers okay?"

She throws him a startled glance. "They're fine." The last time she checked on them, they were sleeping in a pile, so tangled up she could hardly tell one from another. "They're just, you know, doing snake things."

Raphael nods, jaw tight. "I want to see them."

"That's not part of the plan," Karai says, suppressing a sigh.

"I'm already here."

"To get to my quarters, you'll have to go through parts of the building where people are," she points out. "There's too much risk someone would see you."

"I want to know they're okay."

"I just told you!" Karai snaps.

He glares at her, almost growling, and Karai rolls her eyes and turns away. "Fine, do what you want. If you get caught again, don't expect me to bail you out." She stalks over to the closest mutagen tank and checks to make sure it's secured and not leaking.

She keeps her back turned resolutely, and after a moment, Raphael says, "That's it? You're not going to argue with me any more?"

"That ever stopped you from doing what you wanted?" She glances over her shoulder. "Look, I know my word isn't worth much to you, but I give it to you anyway. They're as healthy as I can get them. You were fine, weren't you? And it'll only be a few more days if we can just get this mutagen crap out of here."

He's frowning, narrow-eyed, but finally he gives her a reluctant nod, and together they maneuver the drum of mutagen onto a dolly and slip back toward the loading dock. Karai goes first, sticking to shadows and scouting out the way, letting Raphael haul the container. He's stronger than she is, anyway. Might as well put the extra muscle to use.

This time April and Casey are waiting in the turtles' ridiculous van. Karai really wishes they'd managed to steal something less conspicuous. "This enough?" she asks April as Raphael and Jones shove the mutagen into the van.

The other girl bites her lip. "I'd feel better if we could get more. Do you think we could manage one more tank?"

"Better hurry," Karai mutters.

April comes along; in her current black get-up, she could almost pass for a Foot ninja herself. One more tank, one more trip to the loading dock—

Of course, that's when Stockman comes back.

In spite of their training, none of them sees him coming. He swoops in from somewhere in the ceiling, hissing furiously. It takes Karai a moment to make out his words: "S-s-s-stealing my mutagen!"

Raphael, weapons already in hand, takes a swipe at Stockman, which he dodges, chittering. He's not as strong as most of the mutants, but his ability to fly gives him an advantage that's hard to beat. "Wait!" Karai cries, throwing up a hand. "Stockman, wait. Think about it."

Stockman hovers in mid-air, buzzing to himself. If Xever's face is hard to read these days, Stockman's is indecipherable. She can't even tell where the giant compound eyes are looking, but she can tell that he's noticed what she wants him to see when he says, "Turtle. Here, not s-s-snake."

"That's right," Karai says, still wary, but he seems willing to cease attacking for now. "There's a way to reverse the mutation, Stockman."

"If you let us take the mutagen, maybe we can help you," April says, picking up Karai's cue.

"Baxter S-Stockman doesn't need your help." Stockman zips toward her. April draws her own weapon, and Raphael growls and readies to spring.

"Don't you? We can make retro-mutagen," April says. "It's up to you whether we make any for you."

Stockman snarls at her, pulling back, and Karai adds smoothly, "Everyone knows you're an expert in robotics, not genetics."

"It's a fair trade," April suggests. "Let us take this, and you can have your life back."

Karai waits, ready to act, while Stockman hovers, staring at them, until he finally says, "Go. Take it. I'll keep s-s-s-silent."

#

It takes three days for April and Irma to make the retro-mutagen.

Karai spends those three days on pins and needles, trying to look normal, hoping that Stockman won't let anything slip, that Xever hasn't put too many pieces together, that Bradford and Tiger Claw won't get a whiff of what's going on. She trains and runs her patrols, stands guard over the weapons shipments. She has tea with Shredder, quiet and ceremonial, playing the part of the dutiful daughter.

She wonders if he has always only been playing the part of her father.

When they have drunk their tea, he tells her that they will be returning to Tokyo in a week's time. Karai bows her head and says, "Yes, father." Once she would have been glad to return to her old home, to familiar ground. But that was before. Too much has happened. When she lived in Tokyo, she was Oroku Saki's daughter.

Now, she is no one's.

She had thought removing one snake from the tank was difficult, but removing the remaining three is ten times worse. They resist being separated; they twine together and bite at her and hiss so loudly she whispers, desperately, "Quiet! Someone will hear you!"

By all rights, they shouldn't understand her, but she thinks they subside a little, watching her with slitted, unreadable eyes. She is forced to put them all into the same container, which she slings over her shoulder before stealing into the air vents one more time. Now she just has to hope that no one will check on her quarters and notice that the snakes' tank is empty.

Raphael meets her on the roof, one building over, a silent bulk sliding out of the shadow. He holds out his hand, and she hands over the container, and for _him_ the snakes relax, loosening their coils. When he reaches in, they do not hiss or bite, and one snake attempts to wind its way around his arm. He murmurs something Karai doesn't hear as he closes up the container, and together they make their way down to the turtles' lair.

Karai fidgets while the others get things ready, barely acknowledging her presence. After what happened with Raphael, this time she'll keep her distance as the snakes transform. So she waits, trying not to do anything obvious like drum her fingers on her arm or rub her palms against her thighs. Soon they'll be back, and then she has an offer to make them. It's more than fair, but she doesn't know what they'll think of it, doesn't know what they'll be ready for. She doesn't know if she can do it on her own.

Karai crosses her arms and tries to look stern while Raphael gets the snakes settled and April gets the retro-mutagen ready. After a brief debate, it looks like they've decided to do all three snakes at once, though it takes some effort for Raphael to keep the three of them separated. April sprays the substance over them and Karai bites the inside of her lip, waiting.

After seeing the transformation once, it ought to seem normal, but it still looks... all wrong. The snakes writhe and twist, bones breaking and splitting as limbs spread out of their bodies, as skin thickens and re-shapes. They make harsh noises that modulate into guttural groans. It's surreal, it looks like something out of a movie, some triumph of special effects, but it's happening right in front of her, and when it's over there are three turtles crouched on hands and knees, panting.

Karai's hands curl into fists. April is biting her lip, body tense, almost bouncing on her feet. Irma fiddles with her glasses, and Casey just stares, until Raphael clears his throat and says, nervously, "Guys?"

One of them says, "Raph?" and then there's a scramble that ends up with all four of the brothers on their knees, arms around each other in a small, tight circle, all of them talking at once so urgently she can only pick odds and ends out of the babble. Karai presses her lips together and waits, feeling suddenly out of place, wondering if they'll agree to what she has to say.

#

April has to hold back from launching herself into the middle of the ring. They're here. They're okay. She did it—well, she and Irma, with help from Casey and Karai—but she brought them back. She has them again, and it's the smallest bit of repayment for all they've done for her. The only thing that dampens her sense of elation is the thought of Splinter. She knows what it's like to lose a father, but she always had the hope of getting hers back—_because _of Donnie and his brothers—and they'll never have theirs again, and Splinter must have died not knowing if his sons would ever be safe, would be themselves, again.

Maybe they feel it, too, because the excited chatter dies down into quiet, though the four brothers still keep hold of each other. Now April ventures forward, smiling hopefully, and as the turtles straighten up she says, "Hey, guys."

"April!" Donnie turns around at once, lighting up into a familiar smile when he sees her. He looks disconcertingly naked without his mask and gear, but he looks so happy for a moment that it's easy for April to overlook it and dash forward for a hug, which Donnie willingly gives. It feels just right, familiar and sure and safe, and her heart is nearly overflowing when she says, "I was so worried I wouldn't be able to get you back."

"But you did," Donnie says, and then Mikey piles onto the hug, unable to hold himself back any more.

April has to hug each of them then, individually and together, even Raph all over again. Casey even gets into it when Mikey tackle-hugs him, too. April's laughing when she finally disentangles herself, reluctantly. She says, "I wouldn't have been able to do it without your notes, Donnie. Or without Irma." She gestures toward her friend, who waves back with a nervous smile from where she stands near Casey. "And... and Karai helped a lot, with materials, and..." She trails off as all three turtles seem to realize for the first time that Karai is here.

Leo takes a step toward her and says, "Are you all right?"

Raph rolls his eyes, while Donnie and Mikey stay still, waiting, and April finds herself almost wanting to defend Karai further, to proclaim that she doesn't mean any harm, even though the _kunoichi_ has fooled her before. Karai blinks at Leo, looking startled, and he adds hastily, "I mean, Shredder didn't... do anything to you... right?"

Karai blinks again and her shoulders tighten. "I'm fine," she says. "But none of us will be if he finds out you four are back in action."


	5. Chapter 5

It takes a lot longer than Karai would like before they can actually talk. All of the turtles want to find their weapons and gear—Raphael follows the other three into the dojo, and when they emerge, they're all masked as well as armed, which is more comforting than Karai would have imagined. They look right that way, and it is easier to imagine them as allies, comrades in arms. But then Donatello starts asking April and Irma all about the formula they created, and wanders into the lab with them, and Michelangelo spends five minutes cooing at the thing in the freezer before insisting that they need food, real food, like _now_. And _that_ leads to a lengthy discussion of what to get and where, with Karai vetoing several locations that she knows used to be watched by the Foot Clan before the other three humans are packed off to collect the food. Karai scowls after them as they go, uncomfortably aware of the time passing. How long before she's missed? Or before Xever or Stockman lets something slip to the wrong person?

And will she be able to persuade the turtles to _be_ her allies, to do what must be done?

"You said you don't think we're safe," Leonardo says to her, after corralling his brothers and finally settling down, the five of them, around the kitchen table.

"No," Karai replies. "I found Shredder in my room once, watching you. He could come in again at any time. Or someone else could. The rank and file won't break into my rooms, but Tiger Claw might, or Bradford. It's only a matter of time."

Leonardo nods, eyes narrowed in thought, but Michelangelo speaks before he can. "Is he gonna care, though? I mean, he already... Sensei..." He swallows, suddenly downcast.

"He got his revenge," adds Donatello, putting an arm around Michelangelo's shoulders.

The four of them lower their heads, grief crashing across their faces. Karai swallows, remembering the sickening sound of blades piercing flesh and bone. She knows they are orphaned, now. They have only ever had one protector and mentor and guide, and now he is gone. But she feels a hot stab of envy, too, that their grief can be so pure and uncomplicated. That's something she'll never have.

"I don't think he'll let you go," she says. Her words fall hard into the silence, and when they look up, Raphael's face is already hardening into anger. "He's not—" She breaks off, struggling for the right words. "He used to be different. Before we knew about you. Since he learned that Hamato Yoshi lived, it's all he's talked about. Everything has been about that. Now he acts like he doesn't know what to do with himself." She hunches her shoulders, shaking her head. "The four of you, he thinks you're tainted. It's not just how much trouble you've caused for the Foot. He thinks of you as Hamato, and freaks. Once he knows you're back, he'll want to root you out. He says... he says that's what the Hamato clan did to his." Karai had been raised on a long catalog of the crimes of the Hamato. She wonders if the opposite was true of them.

The four of them exchange puzzled glances, though, quick and flickering, and Leonardo says slowly, "Sensei never told us anything about that. Though if it's true, he might not have said anything."

Raphael scoffs. "Why would it be true? It's Shredder. He lies all the time."

Karai's mouth twists, even though she knows it's true.

Donatello says, looking around, "We could leave. Pack up what we need and find a new place. Maybe out of the city entirely."

"What?" Michelangelo almost seems to shrink, leaning into him. "Where would we even go, bro?"

"No way," Raphael snaps. "He killed Sensei. We gotta take him out."

Leonardo and Donatello frown, but Karai says, "I was hoping you might see it that way."

Unsurprisingly, Raphael scowls at her now. "Don't think you're going to get another chance to stab us in the back."

"I helped you this far, didn't I?" Karai snaps, trying to hold onto her patience. "And if he finds out I helped you, he'll come after me, too." She closes her hands to keep them from shaking. It's too easy to remember the shock of being shoved into that cell. "We have to end this." She looks at each of them in turn—Raphael is still glaring, Michelangelo's eyes are wide and worried, Donatello looks thoughtful—and lands on Leonardo. They'll follow his lead, if she can just convince him.

Leonardo's eyes are narrowed in concentration. He takes his time before saying, "We do have to end this. But it's not about revenge."

Raphael growls, and Leonardo shoots him a look. "You know Sensei wouldn't want that. He lost everything he had before, and he didn't seek vengeance. He went into hiding. We could try to do the same, but we know Shredder would come after us. We need to end this so that we can all live safely, not to pay him back for what he's done."

"With Shredder gone, the vendetta ends," Karai says. Some small part of her is wondering how she can say that so easily, how she can discard the years he raised her. But he raised her on lies, and he used her as bait, and she can never trust a thing he says or does again. Besides, she's already tired of the whole concept of revenge. One last strike at the man she calls father, and it'll end.

They all look at her, Raphael frowning, and she insists, "I'm _with_ you. I don't want this to go on any more than you do."

They exchange glances again, and a series of tiny nods, even from Raphael, and Karai finds herself envious again, this time of their silent rapport. When they face her again, all their gazes are steely, and Leonardo says, "Okay. Do you have a plan to propose?"

"None of us can take him in a stand-up fight," Karai says.

Raphael scoffs. "You so sure of that?"

She shoots him a withering look. "I'm the one who trains with him on a regular basis, so yeah, I'm sure of that."

"Come on," Donatello says. "The four of us couldn't beat him all together. Maybe if we could get another rocket launcher—"

"I can't get one that quickly," Karai says.

Donatello nods. "We could try it with five of us—" He gives Karai a wary look.

She says, "We need to get him alone. We need Tiger Claw out of the picture, especially."

Leonardo nods, eyes narrowed in concentration. Michelangelo says, "What about Fish-face? And Rahzar?" His face screws up. "That dude is like my nemesis."

His brothers all roll their eyes, and Karai's mouth twitches, against her will. "I have an idea about that," she says. "And Xever will side with us, or at least stand by."

Raphael frowns, dubious. "You can't trust that guy."

"I think I know him better than you do," she says.

"Fine." He folds his arms. "Maybe you do, but I don't think _we_ can trust him."

She shrugs. "He can be motivated." There's also her word to Stockman to consider. She looks at Donatello. "We're going to need some more of that retro-mutagen."

It hardly takes a second for his eyes to widen in comprehension. "Oh! Yeah. I see. I'll get on that."

He dashes out of the room. Leonardo says, "Okay. How do we get to him alone? Tell me about the building's layout."

Karai glances at him with a raised eyebrow. "You lot never had any problem breaking in before."

He smiles, for the first time since this conversation started: sharp and tight and yet looking more like his old self again. "It's always good to have insider knowledge."

She smiles back. "Got pen and paper?"

#

By the time April gets back from the pizzeria with Casey and Irma, lugging boxes of pizza, a bag of garlic bread, and bottles of soda, the turtles and Karai are in a council of war. The cheerful mood the rest of them come in with cools off quickly. The boys all wolf down the pizza, with Donnie zipping back and forth from kitchen to lab, and Raph slipping out to check on the spare weapons and other equipment. Leo and Karai are leaning over a map of the Foot headquarters that Karai has drawn from memory.

April listens, and Casey gets into the discussion immediately, suggesting things to do with homemade explosives, but Irma quiets down, picking at her slice of pizza. "Um," she says, shrinking into herself a little bit. "Are you really planning on- on attacking that place? Because I don't know how I feel about that."

Leo's attention fixes on her immediately. "It's all right—Irma, right? Really, you've helped us so much already, we can't thank you enough. We certainly wouldn't expect you to do anything like this."

"Besides," says Mikey, popping up at Irma's side, "it's kind of a family secret thing."

She twitches at his sudden presence. "Right. The whole... ninja clan... thing."

"I know it's a lot to take in," says Donnie, just back from the lab. "I'm really impressed by the work you and April did on the retro-mutagen, though! And you cracked my cipher, we should totally talk about encryption sometime."

April throws him a sharp look, but he's not blushing or stammering, just smiling and eager, and Irma relaxes a little. "Yeah, that would be fun," she says.

Donnie smiles brighter, and says, "April, could I see you in the lab for a moment?"

"Sure," she says, quickly swallowing her last bite.

As they leave, Leo and Karai seem to be sinking back into a muttered conference, and Mikey is offering to show Irma his comics collection, which April is really not sure is going to go over well, but at least it should keep her from getting too nervous.

"What do you need?" she asks Donnie.

"Could I take another blood sample? We need to make more retro-mutagen."

"Sure," April says, rolling up her sleeve. "I started some of the regular kind when we started yours, though."

"Yeah, that'll help," he says. "I'd like an extra supply, though, just in case."

He takes the blood quickly and almost painlessly, and says quietly, "April, I'd like you to stay back when we attack the Foot base."

April's eyes widen. "What? No way! You guys aren't leaving me behind now. Look what happened last time!"

"That's what I'm worried about," Donnie says, his eyes anxious—in fact, his whole mood feels like an anxious cloud that seems to fill the room. "We didn't really have time to plan last time, and now we do, but we're— I just don't think it's a good idea for you to be involved."

April draws back, stung and furious. After all this, she's still on the outside? She thought she was part of the family. She carries the weapon that should have been Karai's, and she won't give it up. She scowls at Donnie and crosses her arms. "You can't make me stay. I loved Sensei, too."

Donnie flinches. "It's not that. None of us would doubt that."

"Then what?" she snaps.

He turns away to tuck the vial of blood safely away in a padded container. And, probably, so he doesn't have to look at her face. April sets her teeth. "What?" she demands again.

Donnie's shoulders hunch. When he turns his head to look at her, the light turns his eyes nearly blood-red. "We're setting out to kill someone this time, April. I'd rather not have that on your conscience."

April presses her lips together. She'd understood that, from the tone of the conversation in the other room, from the dark currents in the minds around her. They don't usually do that—goodness knows the Kraang always seem to scuttle away, and they might have killed in the heat of the moment before, but this is different. It's a plan. It's real, and serious, but April's not a child any more. She's been training as a _kunoichi_, and her master is dead, and her friends are going to fight for their lives. She's not going to stay home "What if I don't care?" she asks, raising her chin.

"You don't _care_?" Donnie turns back to face her, incredulous. "How could you not care about—" He shakes his head. "Do you think I want to have to do this?"

"But you _are_ doing it!"

"Because it's the only way to keep ourselves safe," he says. "We have the advantage of surprise right now, and not for long. He doesn't know we're coming. Once Shredder's gone, there's no more vendetta. We can focus on the Kraang, or whatever else we need to."

"You can't just leave me out!" April protests, and takes a deep breath, trying to control the urge to shout. "I know this is serious, Donnie, but that's why I want to be involved. I'm part of this, too."

"What if the police get involved?" Donnie asks. "We don't exist, but what if they realized you were there? You could be in a lot of trouble. None of us want that, and what would your father think?"

April scowls but drops her head, letting her bangs shade her eyes. She hasn't figured out what to tell her father yet. "It feels like you're telling me I'm not part of this team. Am I or aren't I?"

"Of course you are!" Donnie takes a swift step toward her and reaches out, but hesitates, not quite touching her shoulder. "We owe you our lives, April. There's nothing we can do to repay that—"

"Don't be ridiculous," she says, reaching out to grab his hand. "I already owed you mine and my dad's, at least twice. This isn't about repaying anything. We're in this together, aren't we?"

Donnie smiles at her, but it's stiff and a little shaky. "Yeah," he says. "I just..."

She squeezes his hand, big and calloused, remembering all those nights she wasn't sure she could get him back. She wants to keep talking, assure him she'll do anything to help them, but instead she bites her lip and waits to see what he has to say.

"We already lost Sensei, and we have to do this," Donnie says, quietly. "I don't want to risk losing you, too."

"You won't," says April, and steps forward to throw her arms around him again. After a moment, she adds, turning so her cheek rests against the tough surface of his plastron, "I don't want to lose you, either. Not again. I was so scared I'd never see you again."

She can hear the rhythm of his heart under her ear. She takes comfort from that, and the way his arms slowly close around her. She'd be content to stand there together all night, but after a while, Donnie says, "I missed you, too. I mean—" He gives her a laugh and a weak smile when April tilts her head to look at him "—I couldn't think much, at all, but I felt like there was something missing."

She smiles back before stepping back, carefully, too aware of the way her own heart is hammering. Donnie says, "Just... really think about it, okay?"

"I've already thought about it," she says.

Donnie frowns, his eyes so troubled that April's almost tempted to give in. She frowns back instead, until he sighs and nods, and then she takes her leave, victorious.

Karai's gone when April gets back to the kitchen, though Leo's still staring at the schematic she sketched. "Where did she go?" April asks.

"Karai? She had to go back so she wouldn't be missed," Leo says. He looks up from the map. "What do you think? Can we really trust her?"

April chews on her lip, considering. Karai has deceived her before, but this time, she feels easier to read, less muddled."I think she's sincere. She believes what she's saying."

Leo nods anyway. "That's good enough."

April drifts closer as he looks down at the plans and says, "What can I do to help?"

"You've already done a lot," Leo says. "We can take things from here."

April isn't about to be put off again. "I want to help," she says firmly.

"Well—" Leo looks up and nods after a moment. "Okay, I have a few ideas. Especially if you and Casey are up for working together."

She smiles. "I think we can do that."

Leo smiles back before turning serious. "Thank you for everything, April. Without you, we'd—"

"Don't mention it," April says, cutting him off. She doesn't want to think about it. They're back now. She leans in for a one-armed hug. "What are friends for?"


	6. Chapter 6

For once, things go more or less according to plan.

The turtles have infiltrated Foot HQ before; it's easier this time, even with April and Casey along, because of Karai's directions. They take out the guards on the roof quickly and quietly, make their way in through the ventilation system, and meet Karai at the agreed-upon location, near the dojo, where no one else should be at the hour.

Fishface is with her. Raph bares his teeth, and April braces at the sight; she's heard too many stories about the fish mutant. It's part of the plan, she reminds herself to calm her nerves. Karai was sure they could count on Fishface.

"Truce, no?" he says, baring his fangs in something like a smile. "You have something I want, so you get my cooperation. We leave old grudges behind us."

"Right," says Leo, although Raph is still glaring and Mikey looks uneasy. "Donnie?"

April has seen it enough times by now, but she still stares in fascination as the retro-mutagen transforms the mutant body, thrashing, back into a human. Fishface—Xever— even stays quiet, teeth clamped against the pain. When it's done April hastily looks away as he shoves aside the robotic legs and oxygen tank he used to wear and stretches to his full height, sighing, "Finally!"

"So we're done now," Raph says, with a warning note.

Xever grins at them. "If you like, turtles. If you're going after Bradford, though—"

"We'll take it from here," Leo says.

Next they circle their way down to Stockman's lab to deliver their other promised dose. Stockman, too, is waiting, buzzing to himself. This transformation goes equally smoothly, and Stockman retreats with barely more than a muttered thank-you, to April's ire.

"He's going to cause trouble," Donnie whispers as they make their way back through toward the living quarters. "He knows too much about Kraang tech, and you know what he's like."

"He's gonna build another lab of doom," Mikey says.

"Maybe," Leo says.

Raph snorts. "You know Donnie's right."

"He's out of the way for now, and we made a deal," Karai says, and they fall back into silence.

They encounter a pair of Footbot guards as they make their way through the building, but the bots are quickly dispatched, and they pick up the pace, trying to avoid being caught by the other nighttime guards.

They make it to the door Karai had identified as Tiger Claw's without further incident, but then they all hesitate, nervous about the next step. Finally Karai says, "I'll do it." She holds out her hand, her face hardening into resolve, and Donnie sets the vial in it after only a moment's pause. She glances at Leo. "Cover me?"

Leo nods and gestures the others to spread out in the corridor. Then he sets his shell to the wall beside the door, and Karai knocks, two soft raps.

It only takes a moment for the door to open. April holds her breath as Tiger Claw leans out, making Karai look tiny and fragile, and says, "Who disturbs my rest? Karai? What—"

She throws the retro-mutagen in his face and flings herself backward, drawing her sword.

For a moment April thinks Karai is going to attack him while he's mid-transformation, but she holds back, only readying herself. The rest of them are similarly braced, and April stifles a gasp as it becomes clear that Tiger Claw is changing into a _tiger_, not a human. "Guys!" Leo calls. April isn't sure what he means, but his brothers seem to know what he wants instinctively. Raph and Mikey wind up and launch themselves into simultaneous flying kicks, forcing the struggling tiger back into its room. Leo reaches in past them to grab the door handle and yank it shut.

They all stare at each other, wide-eyed. "That's not going to hold it forever," Donnie says. Inside its room, the tiger snarls, and the door thuds under its weight.

"Block it with something?" Casey suggests.

"See what you can find," Leo says. "Someone must have heard that, though."

"My room's that way," Karai tells them, pointing toward the next door. Raph and Casey run in that direction, with Mikey and Donnie right behind them. "Only Tiger Claw, Bradford, Xever, and I have rooms in this corridor. And Bradford's out on a mission, that's why we picked tonight. But F- Shredder's quarters aren't far that way." She jerks her head.

There's another roar from inside the room as the boys come back from Karai's room hauling, of all the things, a large, sand-lined tank. April can't stop staring as they shove it in front of the door. She can see a lump of shed snake skin inside it, and realizes it must be the tank Karai was keeping the turtles in.

She clenches her jaw as Donnie says, "It's only going to slow him down."

"It'll have to be good enough," Leo says. "Okay. April, Casey, keep the rest of the Foot out of the way."

"No problem." Casey grins. "Red sets 'em up, and I'll take 'em down."

Raph rolls his eyes. Leo says, "Whatever you need to do. Lead them away if you have to."

"We've got it," April says. "Go on."

The others glance at each other and exchange nods, drawing weapons. April sees the turtles' eyes flick to white as they turn and start down the corridor away from her.

She doesn't have time to watch them go, though, because she hears the slight clank and buzz of Footbots on their way. She exchanges glances with Casey, and the two of them take up positions on opposite sides of the corridor.

Casey's the muscle, April's precision. He knocks the bots down with broad sweeps of his hockey stick; April dodges among them and strikes at their circuits with the edge of her _tessen_. Donnie's showed her where the vulnerable spots are, but it's tricky to hit them just right. Sometimes she needs Casey to keep a bot busy while she finds the right gap between metal panels.

In the meantime, she can't tell how the other battle is going, although she can hear it, all right. No matter what they say about ninjas being silent, the turtles are seldom quiet when they get into a fight. She can hear all four of them shouting in turn, along with the crash and thud of their weapons. That's familiar enough, and even reassuring, except that she can also hear the deeper rumble of Shredder's voice. That sends a chill down her spine. She only saw the man once, and not for long, before he handed her over to the Kraang, but she remembers the coldness in his eyes, and his voice. The noises she's hearing aren't giving her enough to ease her fear. After all of this, after they've come so far, what if they lose now?

She and Casey finish off the first group of four Footbots. April looks back toward Shredder's quarters. The door is open now, and she thinks can see a glimpse of motion inside, flashes of green and silver. She takes a step toward it, but Casey calls her name, and she turns back, to face the next round of Footbots. Six this time. April and Casey are both panting when they finish them off in a shower of sparks, though Casey grins at her and twirls his hockey stick in his hand, trying to look casual, like it wasn't any effort. April smirks back at him and then looks toward the the other end of the hall again, hearing a shout. Leo, she thinks. Then there's an almighty crash, like someone knocked over an entire cabinet of weapons. April looks at Casey. "Do you think we should—"

Before she can finish, another Footbot charges around the corner, and they're back in it—eight bots, this time, and by the time they've got them all down, April and Casey have been pushed partway down the hall. There are heaps of robot parts in front of them, some of them smoking.

Behind them, there's silence.

April's heart clenches in panic. She glances at Casey, wide-eyed, before turning and running down the corridor.

"Aw yeah!" Casey calls, keeping pace behind her. "Red and Jones to the rescue!"

"We are not 'Red and Jones'!" April calls back.

She skids to a halt in the doorway the boys went through, and Casey bumps into her from behind as she stares. The room is a shambles. There _is_ a rack of weapons overturned on the floor, a bed flipped up on its side, a finely painted screen with a giant hole torn through one panel and smaller rips through the others. There is other furniture overturned, so much that April can't take all of it in. Besides, her gaze is fixed on the main thing: the fight is over. Oroku Saki lies on the floor; the turtles and Karai stand around him, still poised to fight, weapons in hand.

"Well?" Shredder's deep voice is ragged and hollow now. "Finish it."

Karai says, "I can—"

"No," Leo says. "We agreed."

"We gotta finish this," Raph says.

"Together," Mikey says, still white-eyed, and with a more serious expression than April has ever seen on him before.

Donnie adds, softer, "All of us are responsible."

They exchange glances.

And then the five of them strike together.

April doesn't mean to, but she flinches and looks away until Oroku Saki's groan dies away.

When she looks back, the turtles stand with slumped shoulders, looking tired. All of them are cut or bruised or both, and Leo's favoring one leg. He says, "Let's get out of here."

"Before Tiger Claw breaks out, 'cause fighting a cat is just wrong, dudes," says Mikey, and now he looks like himself again.

Donnie sighs, "He's a tiger, not a house cat, Mikey," as the turtles troop over to join April and Casey at the door. Karai remains behind, standing quiet and straight and unmoving, looking down.

Leo glances back at her. "Karai? Are you coming?"

She turns without a word to join them.

#

Later, Karai takes to the rooftops, a silent shadow. She looks down at the building where she'd lived, trained, led, and been imprisoned over the last year and a half. The building where she'd helped to kill the man who had raised her.

Leonardo finds her there. She's not surprised. There's not much noise, just a slight scrape and a soft tread, but she has an immediate sense of his presence.

Besides, who else would look for her?

He comes up beside her and hesitates when she doesn't move. "I heard what Shredder said to you," he says.

Karai presses her lips together. He had been lying on the floor where he'd fallen, felled by their combined strikes, and he'd laughed, deep and hollow, and he'd spoken.

_I should have expected this. Treacherous, ruthless, and efficient—you are my daughter after all, Karai. _

"It's not true," Leo says. "I just wanted to say that. He was wrong. You're not that. You don't have to be."

Karai lets out a breath and raises her eyes to the horizon, to the clutter of buildings, tall and angular, that fill the sky. Maybe it's true, maybe it isn't. Hamato Yoshi might have been her blood, but Oroku Saki was the one who raised her. That much is for certain.

Distantly, she wonders whether anything he told her about her mother was true. "Well, it's over now," she says.

"Yeah." Leonardo shifts his weight beside her.

"No more vengeance," she adds. That was part of the point of doing it together. They all had a hand in Oroku Saki's death. They can't blame each other, later on. No regrets, no recriminations. Karai should feel free, she supposes, but she's not sure what she does feel. Not cold, exactly; not angry, not precisely sorrowful, and not quite empty, either. Whatever it is, it's uncertain, and she doesn't like it much. She frowns and rolls out her shoulders. "What happens now?"

He exhales, not quite a sigh. "There's always something. The Kraang are still out there, and they're still after April. We still need to find a way to stop them."

"Right." She'd almost forgotten the alien menace. She shouldn't have; the mutagen was their fault in the first place. If nothing else, they're a target. "Maybe I can help you with that."

"Would you?" Leo sounds surprised, like he hadn't expected anything from her. He adds hastily, "I mean, I didn't come out here to ask you for a favor—"

Karai cuts him off. "Didn't think you did." She looks toward him, at last, and flashes a smile. "I kind of like this planet the way it is, though. More or less, anyway. The Foot's a mess right now, but maybe there are resources that could help against the aliens."

"Yeah, that would be great, if you—" he stops himself and there's a long pause while he stares at her. "You're going back to the Foot?"

She smiles again, thinking ahead. "You're forgetting, Leo. The Foot is mine now, if I want it. And I don't think I want to just let Bradford have it." Although Shredder left people in Japan who should also be considered. She lets her smile fall and inhales slowly. "Besides, there _is_ an alien invasion to stop. That's going to be easier with more than just you four."

"True," he says slowly. "I mean... I think we all made a pretty good team."

"We did," she agrees. They had all worked bizarrely well together, really. As much as the turtles bicker and squabble, they come together when it counts. April and Jones and April's geek friend, too, even if mostly they only tolerate Karai.

"It's strange at home without Sensei," Leonardo says after a short silence, almost like he didn't mean to say anything.

Karai hesitates. She should offer condolences, or something, but she's not really any better at that than she is at apologies or thank-yous. And what happened was her fault, in part, but she saved their lives and offered them the chance for vengeance, too, so that probably clears all debts. She lost her father, too, she reminds herself—either of them, both of them, but— She doesn't know what to say, so she settles for asking, "Are you going to be okay down there, without—"

"I don't know." Leo's voice is quiet now, and his shoulders draw together. "I guess we just have to keep on as best we can. Do our best to- to keep going, keep training. We still have a lot to learn if we ever want to be at Sensei's level."

She hesitates a moment more, and then stretches out a hand to touch his arm, just a quick squeeze. "I'm not exactly done training, either," she says. "I might have some contacts in Japan who can help."

"Thanks," he says.

Before she can stop herself, or regret it, she says, "I— I wish I'd had the chance to know him. Your— Splinter." She takes her hand back and crosses her arms, feeling cold.

"Me too," says Leo, and reaches out to touch her arm, this time. "Hey. Do you want to come down to the lair for a while? There's pizza."

Most of them don't like her much, she reminds herself. And if she wants to take the Foot, there will be things to do; she'll have to stake her claim.

But for now, it's over, and maybe things will be different since they've all fought side by side.

Leonardo is offering her a hopeful smile, so she smiles back. "Okay. For a little while."

* * *

><p><em>And there it is-I have some ideas for a potential sequel, but that wraps up this particular plot arc, at least. Thanks for reading, everyone!<em>


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